Many display applications such as personal data assistants (PDAs), global positioning systems (GPS) and navigation systems incorporating GPS, airline check-in terminals, public computer kiosks, as well as a variety of other system and devices include touch screens that are added onto an information display panel so that a user may effectively see an icon or graphic for a data item or action, and by pressing a finger or stylus on that icon, select data item or action.
Conventional devices routinely provide a separate touch panel that is placed on top of the display so that even though a user may believe he or she is touching the display screen, in fact her/she is providing an input to a separate device attached to the display panel or otherwise interposed between the user and the display device.
These devices therefore must include not only the two panels for the touch input and information display, but must also provide the separate electronic and interfaces to the device and in some instances provide separate driver, operating system, and or application program software for the touch input panel and display panels. Assembly and maintenance costs may also typically increase. All of these additional components add to the cost of the device and where competition is high and profit margins small, the additional cost is unwelcome. In some devices the cost of adding a touch panel to a display panel may double the cost as compared to the display panel alone when it is added after original manufacture.
There is therefore a need for an integrated single low-cost display device that can not only display or output two-dimensional symbolic and graphical information generated by the device, but also includes a sensor array that can receive position sensitive input from a user and communicate such position information to the device.
There is also a need for a sensor array that can be integrated with a display during the manufacture of the display so that the additional cost to manufacture and distribute the input sensor array as a touch screen is of nominal cost.
There is also a need in some environments to provide a non-contact input such as in the form of a pen-light input, so that abrasion and other wear or damage that might result from repeated touching pressure on the input device is reduced thereby extending the life of the device in severe service environments. There is also a need to provide a contact input that does not rely on an external light source such as ambient light or a light pen.